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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
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* See the License for the specific language governing permissions and
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*/
package org.apache.flink.runtime.highavailability;
import org.apache.flink.runtime.leaderelection.LeaderElectionService;
import org.apache.flink.runtime.leaderelection.TestingLeaderElectionService;
import org.apache.flink.runtime.leaderelection.TestingLeaderRetrievalService;
import org.apache.flink.runtime.leaderretrieval.LeaderRetrievalService;
import org.apache.flink.util.Preconditions;
import javax.annotation.Nullable;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
/**
* Leader service for {@link TestingManualHighAvailabilityServices} implementation. The leader
* service allows to create multiple {@link TestingLeaderElectionService} and
* {@link TestingLeaderRetrievalService} and allows to manually trigger the services identified
* by a continuous index.
*/
public class ManualLeaderService {
private final List<TestingLeaderElectionService> leaderElectionServices;
private final List<TestingLeaderRetrievalService> leaderRetrievalServices;
private int currentLeaderIndex;
@Nullable
private UUID currentLeaderId;
public ManualLeaderService() {
leaderElectionServices = new ArrayList<>(4);
leaderRetrievalServices = new ArrayList<>(4);
currentLeaderIndex = -1;
currentLeaderId = null;
}
public LeaderRetrievalService createLeaderRetrievalService() {
final TestingLeaderRetrievalService testingLeaderRetrievalService = new TestingLeaderRetrievalService(
getLeaderAddress(currentLeaderIndex),
currentLeaderId);
leaderRetrievalServices.add(testingLeaderRetrievalService);
return testingLeaderRetrievalService;
}
public LeaderElectionService createLeaderElectionService() {
TestingLeaderElectionService testingLeaderElectionService = new TestingLeaderElectionService();
leaderElectionServices.add(testingLeaderElectionService);
return testingLeaderElectionService;
}
public void grantLeadership(int index, UUID leaderId) {
if (currentLeaderId != null) {
revokeLeadership();
}
Preconditions.checkNotNull(leaderId);
Preconditions.checkArgument(0 <= index && index < leaderElectionServices.size());
TestingLeaderElectionService testingLeaderElectionService = leaderElectionServices.get(index);
testingLeaderElectionService.isLeader(leaderId);
currentLeaderIndex = index;
currentLeaderId = leaderId;
}
public void revokeLeadership() {
assert(currentLeaderId != null);
assert(0 <= currentLeaderIndex && currentLeaderIndex < leaderElectionServices.size());
TestingLeaderElectionService testingLeaderElectionService = leaderElectionServices.get(currentLeaderIndex);
testingLeaderElectionService.notLeader();
currentLeaderIndex = -1;
currentLeaderId = null;
}
public void notifyRetrievers(int index, UUID leaderId) {
for (TestingLeaderRetrievalService retrievalService: leaderRetrievalServices) {
retrievalService.notifyListener(getLeaderAddress(index), leaderId);
}
}
private String getLeaderAddress(int index) {
if (0 <= index && index < leaderElectionServices.size()) {
TestingLeaderElectionService testingLeaderElectionService = leaderElectionServices.get(index);
return testingLeaderElectionService.getAddress();
} else {
return null;
}
}
}